September 6, 2009

Stubai Glacier’s Protective Blanket

Posted by Mauri Pelto

The north facing side of the Stubai Glacier, also referred to as the Schaufel Ferner, that comprises the biggest ski area in the area is open all summer down to the Eisgrat lift station. There are two main lifts that traverse up the glacier, some of the towers for the ski lifts are set right on the glacier. The linear features extending down glacier in this satellite view of the glacier are the ski lifts and the ski runs. stubai glacier viewThe Stubai Glacier has been retreating and thinning significantly as have most all glaciers in the Alps. Austria has a long term program monitoring the terminus position of over 100 glaciers. From 2000-2005 of the 115 glaciers observed and reported to the World Glacier Monitoring Service, all 115 experienced net retreat. The mass balance of Austrian glaciers, which represents volume loss, reported to the WGMS has been averaging a loss of more than 0.5 m per year since 1998. The loss of 5 m of ice in a decade on glaciers like the Stubai represents about 10% of their volume lost this decade. Stubai Glacier has experiences a 33% loss in its area since 1969 shrinking from 1.72 to 1.15 square kilometers (Aberman and others, 2009). This ongoing ice loss prompted the ski area in 2003 to begin to explore means to preserve the glacier and maintain there ski season. They turned to the University of Innsbruck’s Andrea Fischer and Marc Olefs, who explored three means to reduce the summer melting. Olefs and Fisher (2007) Innsbruck University.The first was injecting water during the winter into the cold snowpack to make it denser. This did add mass, but did not reduce the melt rate. The second methods was to pack down the snow periodically in the winter, again making it denser. Likewise this did not reduce ablation. This is not surprising given that ablation rates on dense ice and less dense snow are very similar on glaciers. The third method was to cover the glacier with a blanket, they used both felt and plastic. The plastic was more reflective, thinner and easier to deploy and as seen in the next two photographs blends in well with the glacier surface. The top image is from 070122_austria_glacier_hmed10a.hmediumThis technique reduced ablation by 60%. Is snow making now being employed a better answer? The problem is that even one small glacier ski slope is still a large area to cover. Because of this success in 2005, the ski resort continues to employ these white polyethylene sheets to reduce melting in strategic areas on the glacier. They are typically spread out in May. The sheets can be seen emplaced around the lift towers in particular. The bare ice of the main section of the glacier is an area of 400,000 square meters (4,300,000 square feet) tough to cover with material, even if it is a low cost per square meter. This type of geoengineering applied to just part of one small glacier maybe practical, but it is not practical at a significant scale. The severity of the climate change we are experiencing is emphasized by the extent to which the ski area is being forced to adapt to try and maintain its summer ski area. In the pictures below, the problem is illustrated by the extent of bare glacier ice late in summer. The ski lifts are apparent as are the square snow patches around the lift towers in the upper image. In the lower image the view from the gondola shows a glacier with very little snow remaining, this is a sign of a glacier that is quickly losing mass. 20060727-080631_eisjoch_bahnen_bildstoecklferner_zoom_vo_station_eisgratstubai ablation